February 3, 2016 - Pharmacology

Question 1

Terminology for Cardiac Drugs

Answer 1

Inotropes = Contractility

Vasopressors = SVR

Chronotropes = HR

These can be positive or negative too. For example, beta-blockers are negative chronotropes.

Question 2

Inotropes

Answer 2

Deal with contractility.

Question 3

Vasopressors

Answer 3

Deal with SVR

Question 4

Chronotropes

Answer 4

Deal with HR

Question 5

Receptors of the Nervous System

Answer 5

Muscarinic (ACh) in the Parasympathetic

Adrenergic (a & B) in the Sympathetic

Question 6

Role of Parasympathetic

Answer 6

“Rest and Digest”

Decreases HR and SVR

Question 7

Role of Sympathetic

Answer 7

“Fight or Flight”

Increase HR, SVR, and bronchiolar dilation

Question 8

Alpha-1 Receptors

Answer 8

Located on vascular smooth muscle and a little bit in the heart.

Activation leads to increased contractility of the heart, increased HR, and greatly increased SVR.

Question 9

Alpha-2 Receptors

Answer 9

Located selectively where vasodilation may be beneficial during shock, such as the brain.

Activation leads to selective decrease in SVR.

Question 10

Beta-1 Receptors

Answer 10

Located in the heart.

Leads to greatly increased contractility and greatly increased HR.

Question 11

Beta-2 Receptors

Answer 11

Located in smooth muscle of vessels and bronchi.

Activation leads to decreased SVR and bronchial dilation.

Question 12

Receptor Table

Answer 12

Question 13

Epinephrine

Answer 13

Endogenous release from the adrenal medulla.

Activates a-1, a-2, B-1, B-2 receptors.

Results in increased cardiac output, and greatly increased SVR.

Question 14

Epinephrine Dosing

Answer 14

For cardiac arrest, the IV bolus is 1 mg of 1:10,000

For anaphylaxis, the IM dose is 0.3 mg of 1:1000

Question 15

Dopamine

Answer 15

Natural catecholamine which is a precursor to norepinephrine.

Increases both CO and SVR.

Effects are dose-related. At lower doses it is more of a beta-effect, and at higher doses it exhibits more of an alpha effect.

Used only as a bridge to buy time to get to the cath lab. Increasing SVR is not good in the long-term for MI. Very easy to give. Will actually make an MI worse, but will keep the patient from dying.

Question 16

Atropine

Answer 16

An anticholinergic agent. It is a competitive inhibitor of muscarinic receptors.

Blocks the parasympathetic system to increase HR without increasing SVR or CO.

Question 17

Norepinephrine

Answer 17

An alpha-1 receptor agonist with minimal beta-1 activity.

Greatly increases SVR and keeps CO relatively neutral.

Can be used for uncontrolled bleeding.

Question 18

Dobutamine

Answer 18

Beta-1 receptor agonist with minimal beta-2 or alpha activity.

Greatly increases CO with a slight decrease in SVR.

Be careful. In heart failure, the cardiac output may increase but it may not increase above the point where the SVR drops, and the problem may be made worse. This can be supplemented with norepinephrine which will keep CO the same, but will greatly increase SVR.

Question 19

Medication Graph

Answer 19